Controlling the supply of liquid fuel to internal-combustion engines.



J. IVIcKECHNlE.

CONTROLLING THE SUPPLY OF LIQUID FUEL TO INTERNAL COMBUSTION ENGINES.APPLICATION FILED Nov. 7. I9I6.

l gQ5 3%5o Patented May 8, 1917 IUD ran enarns rniranr oration.

JAMES MQKECHNIE, OF EARROW-IN-FURNESS, ENGLAND, ASSIGNOR TO VICKERSLIMITED, 01? LONDON, ENGLAND.

CONTROLLING THE SUPPLY OF LIQUID FUEL T0 INTERNAL-COMBUSTION ENGINES.

Specification of Letters Patent.

Patented May e, ism.

Application filed November 7, 1916. Serial N 0. 129,953.

To all whom it may concern:

Be it known that I, JAMES MoKEoHNIE, a subject of the King of GreatBritain, residing at Naval Construction Works, Barrow-in-Furness, in thecounty of Lancaster, England, have invented certain new and usefulImprovements in Controlling the Supply of Liquid Fuel toInternal-Combustion Engines, of which the following is a specification.

This invention relates to internal combustion engines of the type inwhich liquid fuel is injected into the working cylinder by means of apump and the chief object of the invention is to provide improved meansby which the supply of fuel may be controlled so as to give maximumefficiency for varying load on the engine.

According to this invention the power of the engine is controlledthrough both the fuel pump suction valve and the injection valve bysimultaneously varying by .a common control gear the efiective clearancebetween levers effecting the operation of the two valves and theirrespective cams. For this purpose the -two valve levers are preferablymounted upon eccentric pivots, which are moved simultaneously so as toalter the position of the two axes. The pump (one being employed foreach cylinder in a multi-cylinder engine) acts as a measuring pump todetermine the quantity of fuel injected for each working stroke of theengine, while the injection valve serves to time the injection and tomaintain a high injection pressure as the power is reduced. A resilientaccumulator may be interposed between the pump and the injection valveand the pump may discharge part or all of its charge into thisaccumulator before the injection valve opens.

The form of the injection valve cam is so related to the eccentricdisplacement of the lever axis that the opening of the valve is timed togive the best result for all variations in power given by the adjustmentof the suction valve lever, so that separate timing gear is notnecessary. The displacement of the end of the lever is both radial andcircumferential to the cam to allow the cam to be given a practicableshape for correct timing. The reduction of duration of opening of theinjection valve as the clearance is increased prevents excessive fall ofinjection pressure at reduced powers. The cam operating the pump suctionvalve is preferably made with a steep leading edge giving mechanicalopening of the valveearly in the suction stroke of the pump plunger. Thefollowing edge has a much more gradual slope so that the position ofclosing of the suction valve may be varied over as wide a range as maybe desired during the discharge stroke of the pump, by variation of theclearance between the cam and the valve lever, as already described. Thequantity of fuel delivered depends upon the length of the effectiveportion of the discharge stroke, that is, the portion during which thesuction valve remains closed.

The shaft of the common control gear may be turned under both hand andgovernor control, a clutch being fitted which disengages the governorfrom the shaft upon operation of the hand control, thus rendering itunnecessary to overpower the governor.

In order that the said invention may be clearly understood and readilycarried into effect, the same will be described more fully withreference to the accompanying drawings, in which Figure 1 shows part ofone element of a multi-cylinder engine fitted with a separate fuel pumpfor each cylinder and with a governor controlled fuel injection deviceaccording to this invention; and

Fig. 2 is a detail view of a slight modification.

A. is the fuel injection valve in the cylinder cover B. G is the highpressure fuel oil pump driven ofi' the cam shaft D. 1 E is a rockshaftthrough which the control of the injection valve and fuel pump isefiected, this rockshaft being actuated by means of the centrifugalovernor F through the oil operated relay in known manner, or, ifdesired, alternatively by hand gearing such as the lever H, connecteddirectly to the rock-shaft. The gear is shown approximately in itsnormal iunning position.

The rockshaft E is controlled from the governor through the lever Jwhich is free to turn on the pin it, on which the hand lever H is keyed.This lever J has secured to it the quadrant 7', and the hand lever Hengages this quadrant through the pawl h I v gaged the lever H inoveswith the lever J.

Kim.

The link (3 and lever e transmit the motion of the'lever H to therockshaft E, so that for anymovement of the governor due to a variationin the speed of the engine a correspondingmovement of the rockshaft Eisobtained] Whenthe lever H is gripped ifor hand regulation of-the enginethe grip lever h? withdraws the pawl iz/ from the quadrant .notch sothat thegovernor. is disconnected and the rockshaft E can be turnedwithout requiring the'governor to be overpowered, either at starting orduring runn ng I. The'injection valve A is operated by the cam K- on thecam shaft D through the valve lever L, in the end of which is-the camroller Z. This lever is mounted upon aneccentric fulcrum pin M which isadapted to be partly rotated by' the rockshaft E through levers m and mand link m m is-theeccentric portion of the fulcrum pin M, shown. indotted'li'nes. Upon this pin being. partly rotated by thev rockshaft Eit imparts to the roller Z a radial displacement relatively to i the camK, thus altering thev clearance 00 between the cam roller Z and cam K,this either increasing or decreasing the angle 00 of duration ofinjection according to the direction of rotation of the rockshaft E,causing the roller to work on I the lower or. higher part of the cam.

The-center of the eccentric m is so chosen that it gives to ,the rollerZ, upon partial rotation-of the fulcrum pin M, a tangential as well as aradial displacement about the center of the camshaft D, and the leadingedge of the cam is so correlated to the total displacement imparted tothe roller Z that, for

all adjustments of the fulcrum pin M, the point of opening of theinjection valveA is either maintained practically-constant for' aconstant speed engine such-as a dynamo r engine or advanced and delayedfor a variable, speed engine such as a marine engine,

insuch'a'imanner that the valve is timed to open always at the point inthe /engine" stroke which gives the best result forfany variation inpower given;by the adjustment of the suction valve lever, so thatseparate timing gear is not necessary. v

The Plunger c of the fuel pump C is driven ofi'fthe camshaft D by the'eccentric d and strap d, 0% showing the center of the eccentric. Fig. 1shows the pump G in section-through the valve boxes. I N is the suctionvalve, and thefuel supply to the 'pump passes through the'pipe n intothe fine strainer n, and thence to the suction valve N. O is thedelivery valve which is normally held upon its seat by the' spring o,the fuel assing through the delivery pipe, 0" to the injection valve A.In this pi e 0 may befitted "a resilient accumulator of fiatpin Theleverg' is mounted upon 3.111

eccentric e on .the rockshaft E and is connected to the lever g by thelink 9 so that upon partial rotation of the rockshaft E and theeccentric e the vertical distance v between the roller 9 and. the pointof con- .tact g of the tappet end of lever Q can be elther increased ordecreased. The push 1 vrod n? keeps'the roller 9 up to the profile ofthe cam K by means of the spring a 5.

The suction valve N is normally maintained upon its'seat by the lightspring a andin the illustration the push rod 01. is shown just leavingthe suction valve N on its seat, that is to say the valve is justclosing during the delivery stroke of the pump plunger 0, giving aneffective delivery stroke measured by the angle 00 at the cam shaft D.By suitably choosing the size of the eccentric e and by so shaping 1 theclosing face 9 of cam Q wecan arrange for the valve N to close at anydesired angle on the delivery stroke of the plunger 0, giving-apredetermined effective delivery of oil, for each position of therockshaft E. The leading face 9 of the-cam gives mechanical opening ofthe suction valve early in the pump suction stroke. The angles'w, and mare not usually equal or 00- incident, the angle 01: measuring theefiFective stroke of the pump and hence the amount of the fuel charge,which is stored by the accumulator P and is then injected through aperiod measured by the smaller angle 2?. The two angles, however,increase 11 0 and decrease together. I

As hereinbefore set forth the angle m shows the angle of duration of theopening of the injection valve A, which can be either increased ordecreased by partial rotation of the rockshaft E (acting through itsconnection to the fulcrum pin M), so that according to the ratio of thelevers g and g and the size of the eccentric m that is selected, eachangular position of the rockshaft E from its maximum to its out outposition gives a definite angle of duration m ,1 and the closing face 9of the cam Q, is. so correlated as to close the suction valve N at apredetermined position of the pump plunger 0 on its delivery strokewhich gives a charge of oil corresponding with the amount required forthe angle of duration :12, for all adjustments of the rockshaft E. Thethrow of the cam Q isfmade large enough to insure a suficient opening ofthe valve N when the rockshaft E is at its maximum power adjustment- Ris a lever by which each individual pump-can be cut out independentlythrough the bell crank lever 1', which depresses the suction valve Nindependently of the common control gear and thus renders the pumpinoperative.

Fig. 2 shows an alternative arrangement of the rockshaft E and pin 9upon which levers g and g are mounted. The cam lever g is in this casemounted on the eccentric e of the rockshaft E so that the roller 9 isdisplaced both radially and circumferentially of the cam Q. In thisarrangement the opening or leading edge 9 of the cam Q is so shaped andthe eccentric is so chosen that the tangential displacement imparted tothe roller 9 upon partial rotation of the rockshaftE maintains thetiming of the opening of the suction valve N practically constant forall adjustments of the rockshaft E. That is, the path of adustment ofthe roller 9 follows substantially the outline ,of the leading edge 9 ofthe cam.

What I claim and desire to secure by Letters Patent of the United Statesis 1. In an internal combustion engine, a fuel injection valve by whichliquid fuel is sprayed into the cylinder, a fuel pump including amechanically controlled suction valve, a pair of adjustable lever andcam de- "lces' for operating the said injection and suctlon valves and acommon control gear adapted simultaneously to vary the adju stment ofthe lever and cam devices for both of the said valves.

2. In an internal combustion engine, a fuel injection valve by whichliquid fuel is sprayed into the cylinder, a fuel pump-including amechanically controlled suction valve, a pair of adjustable lever andcam devices for operating the said injection and suction valves, meansfor varying the effective clearance between the valve levers and theirrespective cams and a common control gear adapted simultaneously toactuate the said varying means of the lever and cam devices of both ofthe said valves.

3. In an internal combustion engine, a fuel injection valve by whichliquid fuel is sprayed into the cylinder, a fuel pump including amechanically controlled suction valve, a cam for operation of theinjection valve, an injection valve lever mounted on an eccentricallyadjustable pivot, a cam for operating the pump suction valve, aneccentrically pivoted suction valve lever actuated by the said cam and acommon control efjection valve lever and engine regulating mechanismoperatively connected to the said rockshaft for simultaneous adjustmentof the two levers.

- 5. In an internal combustion engine, a fuel injection valve by whichliquid fuel is sprayed into the cylinder, a fuel pump including amechanically controlled suction valve, a pair of adjustable lever andcam devices for operating the said injection and suction valves, anengine governor, hand regulating mechanism, control gear adapted foroperation by both the governor and the hand regulating mechanism andadapted to vary the adjustment of both of the lever and cam devicessimultaneously and means for disconnecting the hand regulating mechanism from the governor.

6. In an internal combustion engine, a fuel injection valve by whichliquid fuel is sprayed into the cylinder, a fuel pump including amechanically controlled suction valve, a pair of adjustable lever andcam devices for operating the said injection and suction valves, anengine governor, a hand regulating lever normally operated by thegovernor mechanism, control gear connected to and operated by the saidlever and adapted to vary the adjustment of both of the valve lever andcam devices simultaneously and means for disconnecting the said hand iture. v JAMES. MoKEGI-INIE.

